Linksys and laptop compatible?

Been using this new hp laptop 8.1 with my old century link dsl m1000 ethernet modem that has no wifi connection to it.
But now was given an old Linksy wireless-G 2.4GHz router to use for wifi.
Would like to know if anyone knows if this router is compatible with 8.1 or not?
I pushed reset button and typed correct number in browser to get into setup and renamed connection 'mosie' lol.
but can't find setting to make it need a password for connection.And it has a warning sign about connection.
But now wont connect at all and I read some where about possible wireless-G may not be compatible.
I have had desktop for 15yrs and this wireless is all new to me.
Thanks,mosie

In mourning for my Win XP Desktop while using a HP laptop Win8.1
Some times I am confused an some times not.

If what you posted is correct you have a problem. Your old unit was a Modem/Router the Linksys is just a Router. Thus it will NOT connect to your ISP's servers.

Now if you connect one of the ports of the Modem/Router to the Linksys you can then turn off DHCP in the Linksys setup and then go to the wireless/security section of the setup software to setup the Security protocol WEP, WAP, WAP2 (prefered) and the password.

I don't really follow your question, but it's the newer adapters in the 8.1 machine that will be utilised without changing his physical set up from just the m1000 Ethernet modem and using the second method, the computer's wireless adapter should be compatible - although I've never had to perform this op myself as I have a modem/wireless router combo.

I need to clarify> My Actiontec M1000 dsl modem has a spot on top for a wifi module but can not find where anyone still sells them. And I also have a Linksy G router.I ran the ethernet cord from modem to router and it said I had connection but had a warning not secure.I put numbers in browser to get in setup for router and found where I could call wifi connection what I wanted. But could not find place for setting up a password. I will go back and look for where I can turn off DHCP and try again.
I want a secure connection for my 1 laptop only.
Thanks, be back later

In mourning for my Win XP Desktop while using a HP laptop Win8.1
Some times I am confused an some times not.